The above two vehicles are based on ideas from Bram's LEGO® Page.
A Couple of action scenes
The above vehicle is built from the LDRAW instructions on Thomas' LEGO® Trains Page.
All the vehicles below have fold down rail wheels so that the vehicle can ride on the train tracks to where it needs to go.
A diesel truck transporter (3 axle hi-railer) with rail wheels to move track servicing supplies and equipment
Different version of the above Hi-railer
A rail capable box van for carrying supplies and equipment
A Two passenger cab with side compartments and a crane in the back for moving things around at a work site
A road and rail capable crane for big jobs